1. Field of the Invention
This invention relates to methods of forming chuted mixers of the type commonly used in gas turbine aircraft engines.
2. Summary of the Prior Art
In the course of gas turbine engine development, various thermodynamic concepts have evolved which require the mixing of two separate gas flows in an efficient manner. Frequently this mixing is required because the two gas flows are at widely varying temperatures and/or pressures and they must be combined together to form a single homogeneous flow of gases.
Because the current gas turbine aircraft engine is usually a machine that is circular in cross section with various structures emanating radially about an engine centerline, many of these gas flows that must be mixed are circumferential or ring-like in cross section. Therefore, when these gas flows are mixed, the pattern of the mixing is often radial in direction across a circumferential or ring-like cross section.
Various structures have been developed to accomplish radial mixing of gas flows. One structure that is used to accomplish this purpose is commonly referred to as a chuted mixer. Examples of chuted mixers are disclosed in U.S. Pat. No. 4,265,646, Weinstein, et al, and U.S. Pat. No. 3,861,140, Krabacher. Essentially the chuted mixer structure is a ring provided with lobes or chutes extending in a single direction in respect to the ring. These chutes accomplish a function of directing a gas flow originating radially to one side of the mixer and directing that gas flow radially to the opposite side of the mixer. These chuted mixer structures are well known to those skilled in the art and have been used frequently in the aircraft engine industry.
While such chuted mixers are very useful as a gas flow mixing device, they are not particularly simple to manufacture. One previous construction method involves manufacture of several individual lobe structures that are welded together to form a single mixer structure. After individual lobes are connected to form a circular chuted mixer, the mixer has to be reworked in various ways in order to attain appropriate dimensions for assembly within an aircraft engine. Proper sizes and tolerances have been difficult to attain in the course of this reworking. Additionally, this method of construction has required considerable time and effort on the part of skilled machine operators.
Therefore, it is an object of the present invention to provide an improved method of construction of a chuted mixer that attains dimensional measurements and tolerances without requiring reworking and remachining to attain appropriate dimensions.
It is another object of the present invention to provide a method of manufacturing a chuted mixer that does not require joining of individual lobe structures to fabricate a complete daisy mixer.
It is another object of the present invention to provide a method of manufacturing a daisy mixer with cold metal pressing and forming techniques that do not require extreme stretching or reforming of a metal blank so as to avoid tearing or severing the blank.